Background Neuroimaging and lesion studies suggested that the dorsolateral prefrontal and posterior parietal cortices mediate visual metacognitive awareness. The causal evidence provided by non-invasive brain stimulation, however, is inconsistent. -/- Objective/hypothesis Here we revisit a major figure discrimination experiment adding a new Kanizsa figure task trying to resolve whether bilateral continuous theta-burst transcranial magnetic stimulation (cTBS) over these regions affects perceptual metacognition. Specifically, we tested whether subjective visibility ratings and/or metacognitive efficiency are lower when cTBS is applied to these two (...) regions in comparison to an active control region. -/- Methods A within-subjects design including three sessions spaced by one-week intervals was implemented. In each session, every participant was administered bilateral cTBS to either prefrontal, control or parietal cortices. Two concurrent tasks were performed, a real and an illusory figure task, stabilising objective performance with use of an adaptive staircase procedure. -/- Results When performing the replicated task, cTBS was found insufficient to disrupt neither visibility ratings nor metacognitive efficiency. However, with use of Kanizsa style illusory figures, cTBS over the dorsolateral prefrontal, but not over the posterior parietal cortex, was observed to significantly diminish metacognitive efficiency. -/- Conclusion(s) Real and illusory figure tasks demonstrated different cTBS effects. A possible explanation is the involvement of the prefrontal cortex in the creation of expectations, which is necessary for efficient metacognition. Failure to replicate previous findings for the real figure task, however, cannot be said to support, conclusively, the notion that these brain regions have a causal role in metacognitive awareness. This inconsistent finding may result from certain limitations of our study, thereby suggesting the need for yet further investigation. -/- . (shrink)

Negative subjective reports such as “I didn’t see the stimulus” can be interpreted as indicating either that the subject didn’t see the stimulus, or as indicating that, while the subject did see the stimulus, the strength of sensory signals associated with the stimulus fell below a conservative criterion for answering “seen”. Determining which of these two interpretations is correct is the criterion problem. I present two ways in which researchers can solve this problem. But there’s more. What I call the (...) “new criterion problem” consists in determining whether criteria effects reflect perceptual changes, or changes in response strategy. Through case studies, I argue that this new version of the problem can be solved as well, although there is currently no systematic way to solve it. I conclude that criterion problems do not constitute good reasons for skepticism about the scientific study of consciousness. (shrink)

The introspective devices framework proposed by Kammerer and Frankish (this issue) offers an attractive conceptual tool for evaluating and developing accounts of introspection. However, the framework assumes that different views about the nature of introspection can be easily evaluated against a set of common criteria. In this paper, I set out to test this assumption by analysing two formal models of introspection using the introspective device framework. The question I aim to answer is not only whether models developed outside of (...) philosophy can be successfully evaluated against the set of conceptual criteria proposed by Kammerer and Frankish, but also whether this kind of evaluation can reveal some limitations inherent to the framework. (shrink)

Studying consciousness requires contrasting conscious and unconscious perception. While many studies have reported unconscious perceptual effects, recent work has questioned whether such effects are genuinely unconscious, or whether they are due to weak conscious perception. Some philosophers and psychologists have reacted by denying that there is such a thing as unconscious perception, or by holding that unconscious perception has been previously overestimated. This article has two parts. In the first part, I argue that the most significant attack on unconscious perception (...) commits the criterion content fallacy: the fallacy of interpreting evidence that observers were conscious of something as evidence that they were conscious of the task-relevant features of the stimuli. In the second part, I contend that the criterion content fallacy is prevalent in consciousness research. For this reason, I hold that if unconscious perception exists, scientists studying consciousness could routinely underestimate it. I conclude with methodological recommendations for moving the debate forward. (shrink)

Phillips argues that blindsight is due to response criterion artefacts under degraded conscious vision. His view provides alternative explanations for some studies, but may not work well when one considers several key findings in conjunction. Empirically, not all criterion effects are decidedly non-perceptual. Awareness is not completely abolished for some stimuli, in some patients. But in other cases, it was clearly impaired relative to the corresponding visual sensitivity. This relative dissociation is what makes blindsight so important and interesting.

To study consciousness, scientists need to determine when participants are conscious and when they are not. They do so with consciousness detection procedures. A recurring skeptical argument against those procedures is that they cannot be calibrated: there is no way to make sure that detection outcomes are accurate. In this article, I address two main skeptical arguments purporting to show that consciousness scientists cannot calibrate detection procedures. I conclude that there is nothing wrong with calibration in consciousness science.

Metacognition is the capacity to evaluate the success of one's own cognitive processes in various domains; for example, memory and perception. It remains controversial whether metacognition relies on a domain-general resource that is applied to different tasks or if self-evaluative processes are domain specific. Here, we investigated this issue directly by examining the neural substrates engaged when metacognitive judgments were made by human participants of both sexes during perceptual and memory tasks matched for stimulus and performance characteristics. By comparing patterns (...) of fMRI activity while subjects evaluated their performance, we revealed both domain-specific and domain-general metacognitive representations. Multivoxel activity patterns in anterior prefrontal cortex predicted levels of confidence in a domain-specific fashion, whereas domain-general signals predicting confidence and accuracy were found in a widespread network in the frontal and posterior midline. The demonstration of domain-specific metacognitive representations suggests the presence of a content-rich mechanism available to introspection and cognitive control. (shrink)

Critics have often misunderstood the higher-order theory (HOT) of consciousness. Here we clarify its position on several issues, and distinguish it from other views such as the global The higher-order theory (HOT) of consciousness has often been misunderstood by critics. Here we clarify its position on several issues, and distinguish it from other views such as the global workspace theory (GWT) and early sensory models (e.g. first-order local recurrency theories). For example, HOT has been criticized for over-intellectualizing consciousness. We show (...) that while higher-order states are cognitively assembled, the requirements are actually considerably less than often presumed. In this sense HOT may be viewed as an intermediate position between GWT and early sensory views. Also, we clarify that most proponents of HOT do not stipulate consciousness as equivalent to metacognition or confidence. Further, compared to other existing theories, HOT can arguably account better for complex everyday experiences, such as of emotions and episodic memories. This makes HOT particularly useful as a framework for conceptualizing pathological mental states. (shrink)

The present work is concerned with a phenomenon referred to as contextual cueing. In visual search, if a searched-for target object is consistently encountered within a stable spatial arrangement of distractor objects, detecting the target becomes more efficient over time, relative to non-repeated, random arrangements. This effect is attributed to learned target-distractor spatial associations stored in long-term memory, which expedite visual search. This Thesis investigates four aspects of contextual cueing: Study 1 tackled the implicit-explicit debate of contextual cueing from a (...) new perspective. Previous studies tested explicit access to learned displays by applying a recognition test, asking observers whether they have seen a given display in the previous search task. These tests, however, typically yield mixed findings and there is an on-going controversy whether contextual cueing can be described as an implicit or an explicit effect. The current study applied the new perspective of metacognition to contextual cueing and combined a contextual cueing task with metacognitive ratings about the clarity of the visual experience, either of the display configuration or the target stimulus. Bayesian analysis revealed that there was an effect of repeated context on metacognitive sensitivity for configuration, but not target, ratings. It was concluded that effects of contextual memory on metacognition are content-specific and lead to increased metacognitive access to the display configuration, but not to the target stimulus. The more general implication is that from the perspective of metacognition, contextual cueing can be considered as an explicit effect. Study 2 aimed at testing how explicit knowledge affects memory-guided visual search. Two sets of search displays were shown to participants: explicit and implicit displays. Explicit displays were introduced prior to the search experiment, in a dedicated learning session, and observers should deliberately learn these displays. Implicit displays, on the other hand, were first shown in the search experiment and learning was incidental through repeated exposure to these displays. Contextual cueing arising from explicit and implicit displays was assessed relative to a baseline condition of non-repeated displays. The results showed a standard contextual cueing effect for explicit displays and, interestingly, a negative cueing effect for implicit displays. Recognition performance was above chance for both types of repeated displays; however, it was higher for explicit displays. This pattern of results confirmed – in part – the predictions of a single memory model of attention-moderated associative learning, in which different display types compete for behavior and explicit representations block the retrieval of implicit representations. Study 3 investigates interactions between long-term contextual memory with short-term perceptual hypotheses. Both types of perceptual memory share high similarities with respect to their content, therefore the hypothesis was formulated that they share a common memory resource. In three experiments of interrupted search with repeated and non-repeated displays, it was shown that contextual cueing expedites performance in interrupted search; however, there was no interaction of contextual cueing with the generation or the confirmation of perceptual hypotheses. Rather, the analysis of fixational eye movements showed that long-term memory exerts its influence on search performance upon the first glance of a given display, essentially affecting the starting point of the search process. The behavior of approaching the target stimulus is then a product of generating and confirming perceptual hypotheses with these processes being unaffected by long-term contextual memory. It was concluded that long-term and short-term memory representations of the same search display are independent and exhibit additive effects on search performance. Study 4 is concerned with the effects of reward on perceptual learning. It was argued that rewarding repeated displays in a contextual cueing paradigm leads to an acceleration of the learning effect; however, it was not considered whether reward also has an effect in non-repeated displays. In these displays, at least the target position is kept constant while distractor configurations are random across repetitions. Usually this is done in order to account for target position-specific probability learning in contextual cueing. However, it is possible that probability learning itself is modulated by reward. The current experiment introduced high or low reward to repeated and importantly, also non-repeated displays. It was shown that reward had a huge effect on non-repeated displays, indicating that rewarding certain target positions, irrespective of the distractor layout, facilitates RT performance. Interestingly, reward effects were even larger for non-repeated compared to repeated displays. It was concluded that reward has a strong effect on probability-, and not context learning. (shrink)

A series of five experiments investigated the extent of subliminal processing of negation. Participants were presented with a subliminal instruction to either pick or not pick an accompanying noun, followed by a choice of two nouns. By employing subjective measures to determine individual thresholds of subliminal priming, the results of these studies indicated that participants were able to identify the correct noun of the pair – even when the correct noun was specified by negation. Furthermore, using a grey-scale contrast method (...) of masking, Experiment 5 confirmed that these priming effects were evidenced in the absence of partial awareness, and without the effect being attributed to the retrieval of stimulus–response links established during conscious rehearsal. (shrink)

Kammerer and Frankish (this issue) propose an exciting new research programme on the computational form of introspective systems. Pursuing this goal requires measures that can isolate introspective capacity from response biases and first-order processes. I suggest that metacognitive psychophysics is well placed to meet this challenge, allowing the mapping of introspective architectures in humans, animals, and artificial systems.

This paper argues for a position of ‘dark pessimism’ towards introspective reports playing a strong justificatory role in consciousness science, based on the application of frameworks and concepts of measurement. I first show that treating introspective reports as measurements fits well within current discussions of the reliability of introspection, and argue that introspective reports must satisfy at least a minimal definition of measurement in order to play a justificatory role in consciousness science. I then show how treating introspective reports as (...) measurements makes it possible to identify the foundational methodological problems that underlie much of the current philosophical and scientific debate about the status of introspective evidence in studying consciousness. I argue that these problems prevent introspective reports from playing a strong justificatory role and resolving long-standing debates in consciousness science, both in contemporary work and in the future. (shrink)

Block () highlights two experimental studies of neglect patients which, he contends, provide ‘dramatic evidence’ for unconscious seeing. In Block's hands this is the highly non-trivial thesis that seeing of the same fundamental kind as ordinary conscious seeing can occur outside of phenomenal consciousness. Block's case for it provides an excellent opportunity to consider a large body of research on clinical syndromes widely held to evidence unconscious perception. I begin by considering in detail the two studies of neglect to which (...) Block appeals. I show why their interpretation as evidence of unconscious seeing faces a series of local difficulties. I then explain how, even bracketing these issues, a long-standing but overlooked problem concerning our criterion for consciousness problematizes the appeal to both studies. I explain why this problem is especially pressing for Block given his view that phenomenal consciousness overflows access consciousness. I further show that it is epidemic—not only affecting all report-based studies of unconscious seeing in neglect, but also analogous studies of the condition most often alleged to show unconscious seeing, namely blindsight. (shrink)

Consciousness is now a hot topic in both philosophy and the cognitive sciences, yet there is much controversy over how to measure it. First, it is not clear whether biased subjective reports should be taken as adequate for measuring consciousness, or if more objective measures are required. Ways to benefit from the advantages of both these measures in the form of ‘Type 2’ metacognitive measures are under development, but face criticism. Research into neurophysiological measures of consciousness is potentially very valuable, (...) but often hindered by its dependence on behavioural measures that are themselves controversial. Newer informational measures are theoretically interesting, but as yet not easily applicable, while other measures of consciousness are designed for application in clinical cases . Although much optimism accompanies research into measures of consciousness, the controversies and methodological problems reviewed here suggest that making progress in this area may be more difficult than is often acknowledged. (shrink)

This article addresses two issues: the distinction between objective and subjective measures and the directness of such measures. It is argued that the distinction is unambiguous only when based on a methodological criterion rather than a semantic one. Different senses of directness are discussed: metaphysical, methodological, semantic, and causal.

This paper argues for a position of ‘dark pessimism’ towards introspective reports playing a strong justificatory role in consciousness science, based on the application of frameworks and concepts of measurement. I first show that treating introspective reports as measurements fits well within current discussions of the reliability of introspection, and argue that introspective reports must satisfy at least a minimal definition of measurement in order to play a justificatory role in consciousness science. I then show how treating introspective reports as (...) measurements makes it possible to identify the foundational methodological problems that underlie much of the current philosophical and scientific debate about the status of introspective evidence in studying consciousness. I argue that these problems prevent introspective reports from playing a strong justificatory role and resolving long-standing debates in consciousness science, both in contemporary work and in the future. (shrink)

No scientific conclusion follows automatically from a statistically non-significant result, yet people routinely use non-significant results to guide conclusions about the status of theories (or the effectiveness of practices). To know whether a non-significant result counts against a theory, or if it just indicates data insensitivity, researchers must use one of: power, intervals (such as confidence or credibility intervals), or else an indicator of the relative evidence for one theory over another, such as a Bayes factor. I argue Bayes factors (...) allow theory to be linked to data in a way that overcomes the weaknesses of the other approaches. Specifically, Bayes factors use the data themselves to determine their sensitivity in distinguishing theories (unlike power), and they make use of those aspects of a theory’s predictions that are often easiest to specify (unlike power and intervals, which require specifying the minimal interesting value in order to address theory). Bayes factors provide a coherent approach to determining whether non-significant results support a null hypothesis over a theory, or whether the data are just insensitive. They allow accepting and rejecting the null hypothesis to be put on an equal footing. Concrete examples are provided to indicate the range of application of a simple online Bayes calculator, which reveal both the strengths and weaknesses of Bayes factors. (shrink)

Neuroscientists have located brain activity that prepares or encodes action plans before agents are aware of intending to act. On the basis of these findings and broader agency research, activity in these regions has been proposed as the neural realizers of practical intention. My aim in this paper is to evaluate the case for taking these neural states to be neural representations of intention. I draw on work in philosophy of action on the role and nature of practical intentions to (...) construct a framework of the functional profile of intentions fit for empirical investigation. With this framework, I turn to the broader empirical neuroscience literature on agency to assess these proposed neural representations of intention. I argue that while these neural states in some respects satisfy the functions of intention in planning agency prospective of action, their fit with the role of intention in action execution is not well supported. I close by offering a sketch of which experimental task features could aid in the search for the neural realizer of intention in action. (shrink)